The original issue was created in vitejs/vite#9694

With Vite 3 the CSS in JS can be of the type

const a = 'foo '+someJS + 'bar';

in practice it is used for calculating relative URLs

When the string is wrapped by this plugin, it is changed to a format where the JS is no longer executed and you end up with something like this in the final CSS

@font-face{font-family:Line Awesome Brands;font-style:normal;font-weight:400;font-display:auto;src:url("+new URL('la-brands-400.c0e32387.eot', import.meta.url).href+");

Not sure if the escaping can be fixed or worked around here or if this needs to be fixed in Vite